Lead pencil and method of making the same



Dec. 27, 1932. N. GONZ'ALEZ 1,892,508

LEAD PENCIL AND METHOD OF MAKING THE SAME Filed March 27, 1931 INVENTORFaraso Gan BY 67. Adan, v ATTORNE S Patented. Bee. 2?, 1932 PATENTNARCISG GONZALEZ, OF NEW? YORK, Y., ASSIGNOR TO EAGLE PENCIL :ZZOMPANY,01" NEW YORK, N. 1., A CORPORATION OF DELAXVAEE LEAD PENCIL AND METHODOF MAKING THE SAME Application filed March 27, 1931. Serial No. 525,863.

This invention relates generally to the manufacture of pencils and hasreference to ways of preparing leads or crayons so as to get a goodadhesion between them and an outer sheath or casing when the variousparts of the pencil are glued or cemented together.

In the manufacture of pencil leads or other forms of marking materialfor pencils, it is customary to include in the material of which theyare composed various greasy or oil materials such as tallow, stearicacid and the like. These greasy or oily materials are u ed in variousways and in varying proportions according to the nature or kind of markit is desired to hav lie. ,encil make. All of them are a source OIdiillculty in get-ting a good adhcss. of the marking material to the Gasr as a result, the leads often have no 'a ing them to the interior ofthe cashond 2 1 ing because the glue or other adhesives commonly usedcannottake hold upon thc greasy surfaces.

An object. of this invention is to change the greasy surfaces of suchleads or marking material so as to remove the greasy etliect and thengive the pieces of marking material a coating of a material which Willprevent grease from exuding from the interior of the marking materialand which coating will at the same time give a surface to which gluesand cements will adhere.

My present invention considered from one aspect relates to the leadsthemselvesas new articles of manufacture; considered from another aspectrelates to the structure of the complete pencil, andfroin a furtheraspect it is concerned with a method of treating the leads.

The result indicated may be obtained in various ways but a satisfactoryWay of carrying out the process is stated below. That statement ordescription is, however. intended only tc he a representative one and itis not the intention to limit the invention to any one particular way ofpracticing it.

The invention particularly. ltlsulu as it relates to th cinn lctc pencilnnrv he more fully understood hy rrter-ancc t-:: the mom panying drawinwherein Fig. l is a disassemliled view showing a pencillead about to beassembled in its sheath, and;

Fig. 2 is an enlarged transverse sectional View through the completelyassembled pencil.

After the leads have been prepared. in the form they are to ha ve whenas embled in pen- Oils they are immer ed in sulphuric acid for I fztlt'llig periods of time depending upon the depth to or?! the tr .in n isdesired to go and the concciuiuition of the acid. Sal phuric acid hasthe advantage of carbonizing any organic grease and thereby removing ordestroying the great-e ctl'cct. After this treatment in the acid thclead-1 may lie-washed in water. This washing may he carried out in acentrifugal machine or h any other pram tical means. llhe leads are thengiven a seeond treatment v-Jith dilute sulphuric acid and while the acidis adhering to them the leads are immersed in a solution of solublesalts which by reaction with the acid will prccipitate on the lcadsin aninsoluble form: A. satisfactory salt solution one oi calcium chloridebut there are other materials whit-h answer the purpose equally as well.'lf'l'ic insoluble prccipita'liou of calcium he the lead will serve as acasing or seal which will prevent the grcasv material in the hodv of thelead from exu: mg and will also form a very -'atis'fact ry surface forth" dhesion of glue or cement when the penci. lo ing assembled.

The two treatments with the sulphuric acid are pre lcrrezl because ofthe fact that a speedicr operation possihle. ll o cre" steps may becoml-inrd. particular hrst acid bath is sullicicn liluta-d.

til) at tl c load. In Fig. 2; l have shown on an cxa geritrd scale t ethickness t to coating which 1 on the lead and t thickness of the {gluewhi -ir s int tcgct h :5- r

tween such coating and the pencil sheath and which intimately bonds thelead coating to the sheath. Here it will be observed that the lead 10 isprovided with the grease impervious coating 12 formed by the processexplained above and having an outer surface which will firmly adhere tothe glue indicated at 13 which unites the coating to the sheath. Thisglue, of course, also serves to secure the two sections of the sheathtogether, although I have not exaggerated the space between the sheathsections to indicate this.

Results which are on the Whole satisfactory have been obtained bymechanically treating the surfaces of the leads to remove the surfacegrease and then carrying out the acid and precipitating treatment asbefore. However, the acid treatment is: more convenient and satisfactoryin results and is naturally preferred.

As above stated, the invention can be carried out in various ways and itis, therefore, not desired to be limited to any particular Way except assuch limitations may appear in the claims which follow.

What is claimed is:

1. A method of coating pencil leads which comprises treating thesurfaces of the leads with sulphuric acid and then, while acid isadhering to said surfaces, immersing the leads in a solution of calciumchloride.

2. A method of coating pencil leads which comprises treating thesurfaces of the leads with sulphuric acid, washing the leads with water,immersing the leads in a weak solution of sulphuric acid, and thenimmersing the leads in a solution of calcium chloride.

3. A method of coating pencil leads which comprises subjecting the leadsto an acid treatment, and then chemically precipitating on said surfacesan insoluble material which will resist penetration by grease.

4. A method of coating pencil leads which comprises treating thesurfaces of leads contaimng greasy material with an acid, and thenprecipitating on said surfaces a reaction material developed from theacid and a salt which will prevent grease from exuding from the leads.

5. A method of treating pencil leads which com rises treating the leadswith an acid capa le of destroying surface grease, and then coating theleads with a material which will adhere to the surfaces of the lead andprevent grease from exuding through the coating.

6. A method of treating pencil leads which comprises treating the leadsto remove surface grease, and then coating the leads with a materialwhich will prevent grease from exuding through the coating and whichwill serve as a binder between the lead and the casin when the pencil isassembled.

7. i method of treating pencil leads which comprises destroying orremoving surface thereof and a grease impervious coating at the outersurface of the lead intimately adhesively bonded to the sheath.

9. A lead pencil including a. lead, a sectional sheath thereabout and abinder means interposed between them preventing exudation of grease fromthe lead and intimately adhesively attached to the sheath.

10. A lead pencil including a sheath, a core of marking material of thetype normally subject to grease exudation, adhesive between the core andsheath, and means preventing grease exudation from the core andestablishing an intimate bond between the core and the adhesivematerial.

11. As a new article of manufacture a pencil lead having a greaseimpervious coating.

12. As a new article of manufacture a pencil lead having a greaseimpervious coating, the exterior surface of said coating beinginherently adapted for intimate adhesive bonding to an enclosing sheath.

13. As a new article of manufacture a pencil lead having a coating ofcalcium sulphate.

In testimony whereof I hereto aflix my signature.

NARCISO GONZALEZ.

